In recent years, as an X-ray detector to obtain an X-ray image by measuring an X-ray, two kinds of imaging means such as a two-dimensional-type imaging means having a light receiving section in a rectangular shape close to a square, and a line-type imaging means provided with more elongate light receiving section, are available.
Digital radiography apparatuses utilizing the former two-dimensional-type imaging means are mostly used as a replacement of conventional X films, and such radiography apparatuses use various kinds of known radiographic principles of transmission images and sectional images.
Meanwhile, the digital radiography apparatuses using the latter line-type imaging means have a mechanism to obtain an X-ray transmission image by scanning an object to be examined using an X-ray slit beam along a predetermined radiographic orbit and tracking an X-ray passing through the object by a line-type imaging means so as to capture multiple strip-type X-ray images, followed by connecting and arranging these X-ray images in chronological order.
Patent Document 1 and Patent Document 2 mentioned below disclose radiography apparatuses which carries out panoramic radiography by means of line-type imaging means.
That is, Patent Document 1 discloses a radiography apparatus which allows versatile selection between panoramic radiography using a film cassette and panoramic radiography using a digital sensor cassette, where a line-type imaging means is used for a digital sensor cassette.
Patent Document 2 discloses a radiography apparatus in which an electric X-ray image detector is arranged as a line-type imaging means in an X-ray light receiving section provided in the center of the front surface of a cassette housing, and electrically controlled by control signals corresponding to rotation of a rotary arm so that an image signal required to generate a panoramic image can be outputted in a form of digital signals by converting the X ray into electrical signals.
Patent Document 3 discloses a medical radiography apparatus in which a vertically mobile patient frame for holding and fixing a head portion of a patient is provided to allow relative positional displacement between the patient frame and a rotary arm rotating its periphery so as to radiograph the desired position.
Patent Document 1: JP-A-H11-104127
Patent Document 2: JP-A-H11-104128
Patent Document 3: JP-A-H07-275240